1. Field of the Invention
The present invention relates to a recharger and, more particularly, to a self-adaptable recharger for identifying various types of batteries and selecting from several recharge programs.
2. Related Prior Art
There are rechargers for nickel-metal hydride (“Ni-MH” or “Ni—H”) batteries and nickel-cadmium (“Ni—Cd”) batteries and other rechargers for alkaline batteries. For recharging an alkaline battery, a current-limited, constant-voltage method or a time-fixed method is used. There are however problems with these methods. Where a current-limited, constant-voltage method is used, the electrolyte in some alkaline batteries could be reduced after repeated recharge and discharge so that the internal resistances are increased. If the saturation cutoff voltage remains constant, the recharge efficiency would be very low. In some other alkaline batteries, some of the zinc paste at the negative electrodes could crystallize so that the internal resistances are reduced. In this case, most of the energy is used to electrolyze water into hydrogen and oxygen in the alkaline batteries. Such hydrogen and oxygen increase the pressure in the alkaline batteries, and the increased pressure might cause leak and explosion.
There is a conventional technique for recharging Ni-MH, Ni—H, lead acid and disposable zinc-manganese batteries. However, a user must use a switch S to select from various values of voltage for recharging different types of batteries. Hence, this technique is not self-adaptable. Moreover, as a serial constant-pressure control method is used, there could be excessive or inadequate recharge and/or leak because the internal resistances and recharge curves change from one battery to another.
There is a conventional recharger for two types of batteries. By measuring the temperature and voltage of a battery under test, an optimal method can be selected from nine available methods. However, this recharger cannot be used for alkaline batteries.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.